WordNet

stake on the outcome of an issue; "I bet $100 on that new horse"; "She played all her money on the dark horse" (同)wager, play
the act of gambling; "he did it on a bet" (同)wager
maintain with or as if with a bet; "I bet she will be there!" (同)wager
second in order of importance; "the candidate, considered a beta male, was perceived to be unable to lead his party to victory"
the 2nd letter of the Greek alphabet
preliminary or testing stage of a software or hardware product; "a beta version"; "beta software"
(biochemistry) a drug that can combine with a receptor on a cell to produce a physiological reaction
a muscle that contracts while another relaxes; "when bending the elbow the biceps are the agonist"
someone involved in a contest or battle (as in an agon)

PrepTutorEJDIC

『かけ』・(…との)かけ《+『with』+『名』》 / かけた物(金) / かけの対象 / 〈金・物〉'を'『かける』 / (かけ事・ゲームなどで)〈人〉‘と'『かけをする』《+『名』〈人〉+『on』+『名』》 / (…に)『かける』《+『on』(『against』)+『名』(one's do『ing』)》
ベータ(ギリシア語アルファベットの第2文字;B,β;英語のB,b に遭当)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/12/26 17:46:20」(JST)

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Salbutamol (albuterol) — an example of β₂ agonist

β₂ (beta₂) adrenergic receptor agonists, also known as adrenergic β₂ receptor agonists, are a class of drugs that act on the β₂ adrenergic receptor. Like other β adrenergic agonists, they cause smooth muscle relaxation. β₂ adrenergic agonists' effects on smooth muscle cause dilation of bronchial passages, vasodilation in muscle and liver, relaxation of uterine muscle, and release of insulin. They are primarily used to treat asthma and other pulmonary disorders, like COPD.

Mechanism of action

Activation of β adrenergic receptors leads to relaxation of smooth muscle in the lung, and dilation and opening of the airways.

β adrenergic receptors are coupled to a stimulatory G protein of adenylyl cyclase. This enzyme produces the second messenger cyclic adenosine monophosphate (cAMP). In the lung, cAMP decreases calcium concentrations within cells and activates protein kinase A. Both of these changes , inactivate myosin light-chain kinase and activate myosin light-chain phosphatase. In addition, β₂ agonists open large conductance calcium-activated potassium channels and thereby tend to hyperpolarize airway smooth muscle cells. The combination of decreased intracellular calcium, increased membrane potassium conductance, and decreased myosin light chain kinase activity leads to smooth muscle relaxation and bronchodilation.

Adverse effects

Findings indicate that β₂ stimulants, especially in parenteral administration such as inhalation or injection, can induce adverse effects:

Tachycardia secondary to peripheral vasodilation and cardiac stimulation; tachycardia can be accompanied by palpitations
Tremor, excessive sweating, anxiety, insomnia and agitation

More severe effects, such as pulmonary edema, myocardial ischemia, cardiac arrhythmia, are exceptional.

Asthma aggravation has been observed in patients using large doses of β₂ agonists, but it is not known if it results from spontaneous course of the disease or adverse effect of the drugs. The excipients, in particular sulphite, could contribute to the adverse effects. The possible loss of the bronchodilator activity of β₂ mimetics could be attenuated by inhaled corticosteroid intake.

Delivery

All β₂ agonists are available in inhaler form, either metered-dose inhalers (MDIs), which aerosolize the drug, or dry powder inhalers (DPIs), which dispense powder which can be inhaled.

Salbutamol (INN) or albuterol (USAN) and some other β₂ agonists, such as formoterol, also come in a solution form for nebulization, which is more commonly used than inhalers in emergency rooms^{[citation needed]}. Salbutamol and terbutaline are also both available in oral forms. Nebulizer form is as effective as administering the drug intravenously.

In addition, several of these medications are available in intravenous forms, including both salbutamol and terbutaline. It can be used in this form in severe cases of asthma, but it is more commonly used to suppress premature labor because it also relaxes uterine muscle, thereby inhibiting contractions^{[citation needed]}.

Risks

On November 18, 2005, Food and Drug Administration (FDA) alerted healthcare professionals and patients that several long-acting bronchodilator medicines have been associated with possible increased risk of worsening wheezing in some people, and requested that manufacturers update warnings in their existing product labeling.

On June 29, 2006, Cornell University and Stanford University researchers reported that a meta-analysis they conducted found that "regularly inhaled β agonists (orciprenaline/metaproterenol [Alupent], formoterol [Foradil], fluticasone+salmeterol [Serevent, Advair], and salbutamol/albuterol [Proventil, Ventolin, Volmax, and others]) increased the risk of respiratory death more than two-fold, compared with a placebo," while used to treat chronic obstructive pulmonary disease (COPD).^[1]

On December 11, 2008, a panel of experts convened by the Food and Drug Administration (FDA) voted to ban the drugs Serevent and Foradil from use in the treatment of asthma. It was shown that, when these two drugs are used without steroids, they increase the risks of more severe attacks. The experts said that two other much more popular asthma drugs containing long-acting β agonists, Advair and Symbicort, should continue to be used.^[2]

Types

They can be divided into short-acting (SABA), long-acting (LABA) and ultra-long-acting β (more specifically, β₂) adrenoreceptor agonists:

Generic name — Trade name

Short-acting β₂ agonists

bitolterol — Tornalate
fenoterol — Berotec
isoprenaline (INN) or isoproterenol (USAN) — Isuprel
levosalbutamol (INN) or levalbuterol (USAN) — Xopenex
orciprenaline (INN) or metaproterenol (USAN) — Alupent
pirbuterol — Maxair
procaterol
ritodrine — Yutopar
salbutamol (INN) or albuterol (USAN) — Ventolin
terbutaline — Bricanyl

Long-acting β₂ agonists

arformoterol — Brovana (some consider it to be an ultra-LABA)^[3]
bambuterol — Bambec, Oxeol
clenbuterol — Dilaterol, Spiropent
formoterol — Foradil, Oxis, Perforomist
salmeterol — Serevent

Ultra-long-acting β₂ agonists^[4]^[5]

abediterol^[6]
carmoterol
indacaterol — Arcapta Neohaler (U.S.), Onbrez Breezhaler (EU, RU)
olodaterol — Striverdi Respimat
vilanterol
- with umeclidinium bromide — Anoro Ellipta
- with fluticasone furoate — Breo Ellipta (U.S.), Relvar Ellipta (EU, RU)

Unknown duration of action

isoxsuprine
mabuterol
zilpaterol — Zilmax

Society and culture

β₂ agonists are abused by athletes and bodybuilders as anabolic performance-enhancing drugs and their use has been banned by the World Anti-Doping Agency except for certain drugs that people with asthma may use; they are also used illegally to try to promote the growth of livestock.^[7] A 2011 meta-analysis found no evidence that inhaled β₂-agonists improve performance in healthy athletes and found that the evidence was too weak to assess whether systemic administration of β₂-agonists improved performance in healthy people. ^[8]

References

^ Ramanujan K. Common beta-agonist inhalers more than double death rate in COPD patients, Cornell and Stanford scientists assert. Chronicle Online. June 29, 2006. Available at: http://www.news.cornell.edu/stories/June06/Salpeter.COPD.kr.html. Accessed June 30, 2006.
^ Harris G. F.D.A. Panel Votes to Ban Asthma Drugs. "The New York Times". December 11, 2008. Available at: http://www.nytimes.com/2008/12/12/health/policy/12fda.html?ref=health. Accessed January 19, 2009.
^ Matera, MG; Cazzola, M (2007). "Ultra-Long-Acting β₂-Adrenoceptor Agonists: An Emerging Therapeutic Option for Asthma and COPD?". Drugs. 67 (4): 503–15. doi:10.2165/00003495-200767040-00002. Retrieved 7 March 2016.
^ Cazzola, Mario; Matera, Maria Gabriella; Lötvall, Jan (15 July 2005). "Ultra long-acting β₂-agonists in development for asthma and chronic obstructive pulmonary disease". Expert Opinion on Investigational Drugs. 14 (7): 775–83. doi:10.1517/13543784.14.7.775. PMID 16022567.
^ Cazzola, Mario; Calzetta, Luigino; Matera, Maria Gabriella (May 2011). "β₂-adrenoceptor agonists: current and future direction". British Journal of Pharmacology. 163 (1): 4–17. doi:10.1111/j.1476-5381.2011.01216.x. PMC 3085864. PMID 21232045. Retrieved 25 March 2016.
^ Beier, J; Fuhr, R; Massana, E; Jiménez, E; Seoane, B; de Miquel, G; Ruiz, S (October 2014). "Abediterol (LAS100977), a novel long-acting β₂-agonist: Efficacy, safety and tolerability in persistent asthma". Respiratory Medicine. 108 (10): 1424–1429. doi:10.1016/j.rmed.2014.08.005. PMID 25256258. Retrieved 25 March 2016.
^ Drug Enforcement Administration. November 2013 Clenbuterol
^ Pluim BM, et al. β₂-Agonists and physical performance: a systematic review and meta-analysis of randomized controlled trials. Sports Med. 2011 Jan 1;41(1):39-57. PMID 21142283

External links

beta-Adrenergic Receptor Agonists at the US National Library of Medicine Medical Subject Headings (MeSH)

UpToDate Contents

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1. 思春期および成人における重症喘息の治療 treatment of severe asthma in adolescents and adults
2. 喘息におけるβ刺激剤：急性期投与および予防的使用 beta agonists in asthma acute administration and prophylactic use
3. 喘息におけるβ刺激剤：長期使用に関する議論 beta agonists in asthma controversy regarding chronic use
4. 最近の上気道感染を有する小児に対する麻酔 anesthesia for the child with a recent upper respiratory infection
5. 幼児における再発するウイルス誘発性喘鳴の治療 treatment of recurrent virus induced wheezing in young children

English Journal

Emerging role of long-acting anticholinergics in children with asthma.

Vogelberg C1.
Current opinion in pulmonary medicine.Curr Opin Pulm Med.2016 Jan;22(1):74-9. doi: 10.1097/MCP.0000000000000229.
PURPOSE OF REVIEW: Although the use of inhaled anticholinergics in obstructive airway disease has been established for several years, the clinical experience using these medications in treating patients with asthma is limited. Only few studies so far have included pediatric patients with asthma, but
PMID 26606079

Adrenergic β2-receptor mediates itch hypersensitivity following heterotypic chronic stress in rats.

Peng XY1, Huang Y, Wang XL, Cao LF, Chen LH, Luo WF, Liu T.
Neuroreport.Neuroreport.2015 Dec 2;26(17):1003-10. doi: 10.1097/WNR.0000000000000458.
Chronic stress is widely considered to trigger or enhance itch, especially for pruritic dermatitis. However, the molecular mechanisms linking chronic stress and itch are still unknown. The present study aimed to elucidate the role of adrenergic signaling in itch hypersensitivity following heterotypi
PMID 26426856

Synthesis and application of boronic acid-functionalized magnetic adsorbent for sensitive analysis of salbutamol residues in pig tissues.

Fan H1, Wang C1, Wei Y1.
Biomedical chromatography : BMC.Biomed Chromatogr.2015 Dec;29(12):1834-41. doi: 10.1002/bmc.3504. Epub 2015 Jun 10.
Salbutamol (SAL) is the most widely used β2 -agonist drug for asthma and chronic obstructive pulmonary patients, but it is also often abused as feed additive. In recent years, the abuse of SAL has led to a large number of food safety incidents. Therefore, the monitoring of SAL residues in animal pr
PMID 26061980